This paper summarizes the research on passive safety of rail vehicles from the perspective of Crash Energy Management (CEM) in recent decades, which covers the analysis of main crashworthiness standards, as well as the latest research progress in theoretical methods, numerical simulation, and experimental technology of rail vehicles crashworthiness. According to the research status of each subject, some weak links and potential research suggestions are pointed out, such as the requirements of CEM in standards, the influence mechanism of the coupler under different collision speeds, structural compatibility and standardization of anti-climbers, the establishment of vehicle structure crashworthiness design method in design-simulation-test closed-loop system, etc. In the future, under the support of mature CEM theory, more detailed and reliable numerical simulation models, more comprehensive vehicle crash test data, and higher computer computing efficiency, the passive safety of rail vehicles will be guaranteed to the maximum extent.
9 September 2023 in Engineering Fracture Mechanics
A method of collaborative simulation of the train collision process using a rigid motion model and a flexible collision model is proposed to solve the problem of the low computational efficiency of the finite element numerical simulation of the train collision process. This study investigated the collision response of a train derailment hitting a platform with different curve radii based on an accident in which a subway train derailed and hit a platform. Based on the results, a collision damage index is proposed to assess the relative degree of damage of train derailment collisions at different curve radii. The results reveal that within a certain radius of the curve (when the impact distance D exists), there is a positive correlation between the curve radius and the collision damage index, and when the curve radius exceeds a certain value (when the impact distance D doesn’t exist), the train and platform don’t collide.
30 July 2024 in Mechanical Systems and Signal Processing
Using dynamic load identification technology to identify the wheel-rail force of rail vehicles is an economical and convenient method for indirect measurement. In this paper an analytical load identification method is proposed. Firstly, based on the theory of structural dynamics, the Duhamel integral is applied, combined with the characteristics of the rail vehicle system, to derive the analytical load identification method. Secondly, the correctness of the method is verified by a multi-degree-of-freedom system with exact solution. Next, a detailed vehicle dynamics simulation model is established as a virtual test vehicle and source of virtual measurements of the vehicle responses (axlebox accelerations). Different operating conditions are considered, and the virtual acceleration measurements are used as input to the load identification method for indirect measurement of the wheel-rail forces. Finally, the identified vertical and lateral wheelset force, vertical force of the left and right wheels, derailment coefficient and wheel unloading rate are compared with the corresponding time-histories from the virtual test-vehicle simulations. A good agreement is found with all of their correlation coefficients above 0.8. This result has important implications on the safety evaluation of vehicle curve negotiation by using acceleration measurements only, without the need for direct force measurements.